Metallurgy of metal sulfids.



E A. ASHCROFT. METALLURGY 0P METAL SULFIDS.

APPLICATION FILED Mn. 9, 1910.

1,91 1,899, Patented Dec. 19,1911.

EDGAR ARTHUR ASHCROFT, 0F SOGN, NORWAY.

METALLURGY 0F METAL SULFIDS.

Specification of Letters Patent.

Patented Dec. 19, 1911.

Application filed April 9, 1910. Serial No. 554,510.

To all whom it may concern:

Be it known that I, EDGAR ARTHUR ASH- CROFT, a subject of the King of England, residing at Sogn, Norway, have invented certain new and useful Improvements in the Metallurgy of Metal Sulfids, of which the following is a specification.

Sult'ids-of metals nearly free from gauges are produced in large quantities from mechanical concentration of the well-known Broken Hill refractory ores which are taken here as sufiiciently illustrative of similar ores which occur with slight modifications all over the world and are likewise'amenable to the treatment herein described.

Two leading products from the concen trating mills are recognized in the arts today viz: (a) zinc concentrates containing upward of 40% zinc and under 12% lead and some silver, and (1)) lead concentrates containing upward of 50% of lead and under 12% of zinc and some silver. Also in smaller quantities (0) intermediate products such as slimes and middlings of varying composition., In treating (a) the process of YlIlC smelting in retort furnaces is the one generally employed and the lead and silver and sulfur are either lost or very imperfectly recovered from the residues at great expense. of lead smelting is now almost universally employed and the zinc and sulfur are lost. The intermediate products (0) are at present only capable of economical treatment by mixing with other ores in smelting furnaces in trifling quantities or by being first converted by mechanical separation in products resembling either (a) or (b) in composition.

The present invention has for its principal object the more economical treatment of the zinc sulfid residues left after the treatculties were experienced in eliminating the In treating (b) the process.

In this process great (ma.

ganguc matter and the iron and manganese chlorids from the fused melts and in recovering the chlorin which is combined with such impurities. In conse uence of which ditliculties this process whic otherwise presents great advantages over other forms of treatment has found a very limited application.

I have discovered that a more practical and economical process for the above pur pose is as described below :-The special features characterizing this process are:(1) Gangue matter is first eliminated as completely as possible from the mixed sulfids' (2) Lead and silver sulfids are decomposed and lead and silver separated and recovered in any usual manner, or preferably according to the methods described in my co-pending applications Serial Nos. 554,508 and 554,509 filed April 9, 1910. (3) The remaining zinc sulfid residues are treated by chlorin (or chlorid of sulfur) smelting followed by electrolysis according to the reaction described in U. S. Patent No. 691,822 with modifications as described below for the elimination of iron and manganese-and recovery of the chlorin which enters into combination with these metals.

Although the above is the preferred method of working step 2 maybe omitted and the lead and silver recovered at subsequent stages of the process when economi' cally desirable.

The chlorin smelting process may be briefly described asfollows:-The ore (from which the gangue has been removed and from which preferably the lead and silver have been substantially removed as above referred to) is made into a cream with fused chlorid of zinc. The cream is treated in a converter or suitable vessel with a chlorinating agent viz., chlorin or sulfur chlorid, the gas or liquid being forced in at the bottom. stance a low red heat) the chlorin is rapidly absorbed by the metals and sulfur is glven oil in its place. The reaction is most vigorous at a temperature of (500 C. and upward which is well above the fusing mint and well below the vaporizing point 0 zinc chlorid, and being exothermic, the temperature may be maintained and regulated by increasing or decreasing the blast of chlorin and regulating the supply of ore. To start the operation it"is convenient to fuse the rhlorils etc. in a separate vessel or large At a suitable-- temperature (for inbe passed and will merely result in raising some of the iron chlorid to the ferric state. The point at which reaction in the converter is complete (all the sulfur present being then eliminated) is clearly and usefully indicated by the disengagement of copious brown fumes of ferric and mangamc chlorids which can be instantly detected by opening a small ,test hole. At the end of the treatment the converter contains var ing quantities of fused chlorids of zinc, lead and silver if present in the ore) and iron and manganese. The iron and manganese are present mainly' as ferrous andmanganous chlorids.

The modifications in the subsequent treatment referred to under (3) above are as follows according to the present invention :-The converter operation, is now carefully regulated and stopped as nearly as possible at the moment that all the sulfur is eliminated from the melt and while the iron and manganese chlorids are still in the ferrous and manganous states and care is taken to prevent much excess of chlorin being introduced beyond this point so as to avoid volatile chlorids such as Fe,Cl,,, M1101,

passing into the sulfur as these destroy its marketable value and are somewhat troublesome to recover or remove. The melt is tapped while still hot into other eonverters, a sufficient quantity of the hot charge being left in the main converter to restart the process with fresh quantities of ore. Escape pipes from the second convertersare carried to an absorption ap aratus as described below. Into the secon converters a slow stream of chlorin is passed from below for a considerable time, and results in the volatilization of the iron and manganese from the melt in the form of the higher chlorids of these metals which are very volatile and tend to leave the melt as soon as formed, if no sulfid is present to react with them re-forming the lower chlorids. A small quantity of zinc chlorid may be carried over mechanically if the temperature is too high. This will, however, be caught in the absorption ap aratus in solution with sodium chlorid an readily recovered either by crystallization as double chlorid of sodium and zinc, which may be electrolyzed' in the principal electrolysis apparatus or as zinchydrate by precipitation with a small excess of soda solution.

A supplementary electrolytic a aratus is provide wherein sodium ohlori posed in aqueous solution, resulting in pure strong chlorin gas '(which-is passed baclr to the converters) and a solution of NaOl'l (with some NaCl which, however, does not interfere) which ma be made of any de sired stren h ref erably about 10% to 15% NaO T isis used in any convenient absorption a paratus for the precipitation of iron an manganese hydrates with the re-formation of'the sodium chlorid solution. The hydrated oxids are filtered hot from the solution of NaCl thus recoverin all chlorin and a by-product of iron an manganese hydrates free from all other impurities. The occluded salt solution may be readily washed out. The iron and manganese hydrates so produced are a valuable by-product, and may be sold as paint or smelted for the production of ferro manganese. These reactions are as follows $8 H,O) 6NaCl 311,0.

The resulting iron free fused chlorids if more metals than zinc are present may be treated for their metallic contents in any well-known manner, as for example by fractional precipitation or fractional electrolysis.- In either case the proportion between the size of the electrolysis vats for treating the fused chlorids and those for manufacture of soda solution for treating the ferric and manganic chlorids, depends upon the composition of the ore and should be correctly balanced.

The accompanying drawing is a diagram representing one arrangement of apparatus suitable for carrying this invention into effect.

A represents a concentration plant of any type suitable for the removal of gangue from sulfids.

The small diagram B. re resents an apparatus of the type describe in my previous U. S. a plication Serial No. 554,508, to indicate t lat at this stage the lead and silver sulfids may be eliminated. The ore, with or without this preliminary treatment, is made into a cream with fused chlorid of zinc and introduced into a converter C through the inlet C Chlorin or chlorid of sulfur is forced in through the twyer or inlet C Sulfur is given off through the outlet C and passes into a condenser D where it is collected.

is decom- The mixed chlorids are removed from the outlet 0 of the converter and introduced through the inlets E into two secondary converters E. Into the secondary converters chlorin is passed through the tw ers or inlets E The iron and manganese c lorids escaping through the outlet E are passed through an inlet F into an absorption apparatus F into which is also introduced caustic soda solution through the inlet F The contents of the absorption apparatus are passed into a filter G from which the sodium chlorid solution produced by the reactions in the tower is withdrawn through ,one outlet G and the iron and mang'anese'hydrates are withdrawn through the out-let G The sodium chlorid solution is passed through an inlet H into an electrolytic vat H from which the chlorin is removed through outlet H to the twyers E of the converters E. The resulting caustic soda solution is re moved through an outlet H and conducted through a pump J to the inlet F of the absorption apparatus F. The fused chlorids in the converters E having been freed from iron and manganese are removed through the outlet E and may be treated for the removal of lead and silver in an apparatus K if this has not already been done; and in any case the fused zinc chlorid is introduced through the inlet L? to an electrolytic vat L from which the chlorin is removed through the outlet L to the twyer C of the converter C and the metallic zinc (final product) is removed from the outlet L As indicated by the dotted line M the chlorin supplies from the two electrolytic vats H and L are interchangeable.

This process is applicable to the treatment of all kinds of sulfid ores and of products such as metals containing other metal-suffids such as nickel, antimony, cobalt, copper and the like and the treatment will of course be modified to suit the particular contents of the ore or product under treatment.

When an ore or product contains antimony or arsenic these elements are converted into highly volatile, and easily fusible chlorids and will leave the melt immediately, thus constituting a valuable means of separation. The typical reaction in such cases is as follows 1-- of zinc chlorid by treatment with zinc oxidaccording to the reaction 8ZnO+2SbCl =Sb O3+3ZnCl The antimony oxid is a valuable product and the zinc chlorid is used again in the process.

The gangue (if any) may be allowed to settle, preferably in a separate vessel and the chlorids poured off during any conven- 'ient subsequent stage of the process for instance in the second converters after finishin the charge or in any of the storage pots.

Vhat I claim as my invention and desire to secure by Letters Patent is 1. A process of treating sulfid ores or products which consists in eliminating the gangue matter, separating the lead and silver present, mixing the remaining product with a fused metal chlorid, subjecting the meltto the action of a chlorinating agent, removing the melt to other converters, and treating the mixture with chlorin to volatilize the iron and manganese as higher chlorids.

2. A'process of treating sulfid ores or products which consists in eliminating the gangue matter, separating the lead and silver present, mixing the remaining product with a fused metal chlorid, subjecting the melt to the action of a chlorinating. agent, removing the melt to other converters, treating the mixture with chlorin to volatilize the iron and manganese as higher chlorids, and thereafter recoverin the other metals present by extracting tfiem by fractional precipitation andelectrolysis.

3. A process of treating sulfid ores or products which consists in eliminating the gangue matter, separating the lead and silver present, mixing the remaining product with a fused metal chlorid, subjecting the melt to the action of a chlorinating agent, removing the melt to other converters, treating the mixture with chlorin to volatilize the iron and manganese as higher chlorids, passing the chlorids to absorption apparatus wherein they are treated with a solution of sodium hydrate to form sodium chlorid and iron an manganese hydrates, and thereafter recovering the;other metals present by extracting them by fractional precipitation and electrolysis.

4. A process of treating sulfid ores or products which consists in eliminating-the gangue matter, separating the lead and sil ver present, mixing the remaining product with a fused metal chlorid, subjecting the melt to the action of a chlorinat-ing agent, removing the melt to other converters, treating the mixture with chlorin to volatilize the iron and manganese as higher chlorids, passing the chlorids to absorption apparatus wherein they are treated with a solution of sodium hydrate to form sodium chlorid and iron andmanganese hydrates, separating and electrolyzing the sodium chlorid for the production of chlorin and sodium hydrate, utilizing the chlorin for reacting with the mixed sulfids and chlorid in the first converter and the mixed chlorids in the second converters,- passing the sodium hydrate to the absorption apparatus to react with the iron and manganese chlorids, and thereafter recoverin the other metals present by extracting t cm by fractional precipitation and electrolysis.

5. A process of treating sulfid ores or products which consists in eliminating the gangue matter, separating the lead and silver present, mixing the remaining product with fused metal chlorid andseparating the antimony present as a volatile chlorid, subjecting the melt to the action of a chlorinatmg agent, removing the melt to other converters, treating the mixture with chlorin to volatilize the i ron and manganese as higher chlorids, passing the chlorids to absorption apparatus wherein they are treated with a solution of sodium hydrate to form sodium chlorid and iron and manganese hydrates, separating and electrolyzing the sodium chlorid for the production of chlorin and sodiumhydrate, utilizing the chlorin for reacting with the mixed sulfids and chlorid in the first converter, and the mixed chlorids in the second converters, passing the sodium hydrate to the absorption apparatusto react.with the iron and manganese chlorids, and thereafter recovering the other \metals' present by extractin them by fractional preci tation and electro ysis.

6. A process o treating sulfid ores or products whichco'nsists in eliminatingthe gangue matter, separating the lead and silver present, mixing the remaining product with fused metal chlorid and separating the arsenic resent, as a volatile chlorid, subjecting t e melt to the action of a chlorinatmg agent, removing the melt to other converters, treating the mixture with chlorin to volatilize the iron" and man anese as higher chlorids, passing thechlorids to absorption apparatus wherein they are treated wit a solution of sodium hydrate to form sodium chloiid and'iron and manganese bydrates, separating and electrolyzing the sodium chlorid for the production of chlorin and sodiumhydrate, utilizin for reacting with the mixe sulfids and chlorid in the first converter, and the mixed chlorids in the second converters, passing the sodium hydrate to the absorption apparatus to re-act with the iron and manganese chlorids, and thereafter recovering the'other metals present by extractingthem by fractional precipitation and electrolysis.

7 A process" of treating sulfid ores or the products which consists in eliminating an 'silgangue matter, separating the lead ver present, mixing the remaining product with fused metal chlorid and separating the antimony present as a volatile chlorid, treating the antimony chlorid with zinc oxid for the chlorin the production of antimony oxid and zinc chlorid which is're-acted with a further quantity of ore, subjecting the melt to the action of a chlorinating agent, removing the melt to other converters, treating the mixture with chlorin to volatilize the iron and manganese as higher chlorids, passing the chlorids to absorption apparatus wherein they are treated with a solution of sodium hydrate to form sodium. chlorid and iron and manganese hydrates, separating and electrolyzing the sodium chlorid for the production of chlorin and sodium hydrate, utilizing the chlorin for reacting with the mixed sulfids and chlorid in the first converter, and the 'mixed chlorids in the second converters, passing the sodium hydrate to the absorption apparatus to react with the iron and manganese chlorids, and there after recovering the other metals present quantity of ore, subjecting the melt to the action of a chlorinating agent, removing the melt to other converters, treating-the mixture with chlorin to volatilize the iron and manganese as higher chlorids, passing the chlorids to absorption apparatus where- 'in they are treated Wltll' a solution of sodium hydrate to form sodium chlorid and iron and manganese hydrates, separating and electrolyzing the sodium chlorid for the production of chlorin and sodium hydrate, utilizing the chlorin for re-acting with the mixed sulfids and chlorid in the first converter, and the mixed chlorids in the second converters, passing the sodium hydrate toithe absorption apparatus to react with the iron and manganese chlorids, and thereafter recovering the other metals present by extracting them by fractional precipitation and electrolysis.

9. A rocess of treating zinc sulfid containing ead and other metal sulfids which consists in eliminating'the gangue matter, separating the lead and silver present, mixin the remaining product with fused zinc ch orid and subjecting the melt to the action.

of chlorin gas, removing the melt to other converters, and treating the mixture with chlorin to volatilize the iron and manganese as higher chlorids;

10. A process of treating zinc sulfid containing lead and other metal sulfids which consists in eliminating the gangue matter, separating the lead and silver present, mm-

ing the remaining product with fused zinc chlorid and subjecting the melt to the action of chlorin gas, removing the melt to other converters and treating the mixture with chlorin to volatilize the iron and manganese as-higher chlorids, and thereafter recovering the zinc by electrolyzing the melt.

11. A process of treating zinc sulfid containing lead and other metal sulfids which consists in eliminating the gangue matter, separating the lead and silver present, mixing the remaining product with fused zinc chlorid and subjecting the melt to the action of chlorin gas, removing the melt to other converters and treating the mixture with chlorin to volatilize the iron and manganese as higher chlorids, passing the chlorids to absorption apparatus wherein they are treated with a solution of sodium hydrate to form sodium chlorid and iron and manganese hydrates, and thereafter recovering the zinc by electrolyzing the melt.

12. A process of treating zinc sulfid containing lead and other metal sulfids which consists in eliminating the gangue matter, separating the lead and silver present, mixing the remaining product with fused zinc chlorid and subjecting the melt to the action of chlorin gas, removing themelt to other converters and treating the mixture with chlorin to volatilize the iron and manganese as higher chlorids, passing the chlorids to absorption apparatus wherein they are treated with a solution of sodium hydrate to form sodium chlorid and iron and manganese hydrates, separating and electrolyzing the sodium chlorid for the production of chlorin and sodium hydrate, utilizing the chlorin for reacting with the mixed sulfids and chlorid in the first converter, and the mixed chlorids in the second converters passing the sodium hydrate to the absorption apparatus-to react with the iron and manganese chlorids, and thereafter recovering the zinc by electrolyzing the melt.

13. A process of treating zinc sulfid containing lead and other metal sulfids which consists in eliminating the gangue matter, separating the lead and silver present, mixing the ore with fused zinc chlorid, and separating the antimony and arsenic present as volatile chlorids, subjecting the melt to the action of chlorin gas, removing the melt to other converters and treating the mixture with chlorin to volatilize the iron and manganese as higher chlorids, passing the chlorids to absorption apparatus wherein they are treated with a solution of sodium hydrate to form sodium chlorid and iron and manganese hydrates, separating and electrolyzing the sodium chlorid for the production of chlorin and sodium hydrate, utilizing the chlorin for reacting with the mixed sulfids and chlorid in the first converter, and the mixed'chlorids in the second converters passing the sodium hydrate'to the absorption apparatus to react with the iron and manganese chlorids, and thereafter reclovering the zinc by electrolyzing the me t.

14. A process of treating zinc sulfid containing lead and other metal sulfids which consists in eliminating the gangue matter, separating thelead and silver present, mixing the remaining product with fused zinc chlorid and separating the antimony and ar senic present as volatile chlorids, treating the antimony and arsenic chlorids with zinc oxid for the production of antimon oxid and arsenic oxid and zinc chlorid w lich is reacted with a further quantity of ore subjecting the melt to the action of chlorin gas, removing the melt to other converters and treating the mixture with chlorin to volatilize the iron and manganese as higher chlorids, passing the chlorids to absorption apparatus wherein they are treated with a solution of sodium hydrate to form sodium chlorid and iron and manganese hydrates, separating and electrolyzing the sodium chlorid for the production of chlorin and sodium hydrate, utilizing the chlorin for reacting with the mixed sulfids and chlorid in the first converter, and the mixed chld rids in the second converters, passing the sodium hydrate to the absorption apparatus to react with the iron and manganese chlorids, and thereafter recovering the zinc by electrolyzing the melt.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

EDGAR ARTHUR ASHCROFT.

Witnesses:

HARRY B. Bnmcn, PERCY HEWITT. 

